Port 1646 is commonly used for authentication services when using Remote Authentication Dial-In User Service (RADIUS) protocol. RADIUS is a networking protocol that provides centralized authentication, authorization, and accounting management for users who connect and use network resources such as Wi-Fi, VPN, and dial-up. Port 1646 is specifically used for RADIUS accounting messages between RADIUS clients and servers.
Ports those registered with IANA are shown as official ports. The same port number may be unofficialy used by various services or applications. The official usage are listed separately below its usage may change from time to time.
Official
Port |
Protocol (TCP/UDP) |
Title |
Description |
Port Type |
Port 1646 |
tcp |
sa-msg-port |
sa-msg-port |
REGISTERED PORT |
Port 1646 |
udp |
sa-msg-port |
sa-msg-port |
REGISTERED PORT |
UnOfficial
Unofficialy or sometimes with conflict, the same port may be used by different applications.
| Port | Protocol (TCP/UDP) | Description |
| Port 1646 | radius acct, RADIUS authentication protocol (default for Cisco and Juniper Networks RADIUS servers) |